id,summary,reporter,owner,description,type,status,component,version,severity,resolution,keywords,cc,stage,has_patch,needs_docs,needs_tests,needs_better_patch,easy,ui_ux 10634,Confusing differential exceptions: get_or_create vs get with psycopg2,fergusferrier,nobody," I'm using Psycopg2. I hope the models here are somewhat self-explanatory in structure. I made the simple mistake of forgetting the boolean 'created' in a get_or_create... {{{ usr = EventsUser.objects.get_or_create(user = request.user) }}} Then running the following code [NB. usr is not an instance of EventsUser at this point]... {{{ Reminder.objects.get_or_create( events_user = usr, event = event, assoctype = 'EML_HR' ) }}} gives thus: {{{ Traceback (most recent call last): File ""/home/django/domains/staging.mypidge.com/project/Apps/Events/tests/views.py"", line 418, in test_set_reminder_unset response = self.client.get(reverse('Events.views.SetReminders', args=[self.event.id]), {'day': '1', 'hour': '1'}) File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/test/client.py"", line 278, in get response = self.request(**r) File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/core/handlers/base.py"", line 91, in get_response response = callback(request, *callback_args, **callback_kwargs) File ""/home/django/domains/staging.mypidge.com/project/Apps/basic/funcs.py"", line 35, in decorator return f(request, *args, **kwargs) File ""/home/django/domains/staging.mypidge.com/project/Apps/Events/views.py"", line 319, in SetReminders assoctype = 'EML_HR' File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/manager.py"", line 120, in get_or_create return self.get_query_set().get_or_create(**kwargs) File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/query.py"", line 365, in get_or_create return self.get(**kwargs), False File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/query.py"", line 337, in get num = len(clone) File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/query.py"", line 161, in __len__ self._result_cache = list(self.iterator()) File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/query.py"", line 281, in iterator for row in self.query.results_iter(): File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/sql/query.py"", line 256, in results_iter for rows in self.execute_sql(MULTI): File ""/home/django/domains/mypidge.com/env/lib/python2.5/site-packages/django/db/models/sql/query.py"", line 2098, in execute_sql cursor.execute(sql, params) File ""build/bdist.linux-x86_64/egg/psycopg2/extensions.py"", line 96, in getquoted pobjs = [adapt(o) for o in self._seq] ProgrammingError: can't adapt }}} When one replaces the second get_or_create with a plain get, you are returned {{{ ValueError: Cannot assign ""(, False)"": ""Reminder.events_user"" must be a ""EventsUser"" instance. }}} which is a much more useful exception. I would expect get_or_create to return a similar.",,closed,"Database layer (models, ORM)",dev,,invalid,psycopg2 get_or_create get misleading,,Unreviewed,0,0,0,0,0,0